The present invention relates to a junction box mounted on a vehicle body. More particularly, the present invention relates to a junction box, disposed between a dash panel and an installment panel, where fuses and relay replacements may be easily accomplished with high workability in a reasonable maintenance time. The present invention also relates to a compact junction box that can be connected to a wire harness with high operability
In the conventional art, two kinds of wire harnesses, namely, an installment panel harness and a cowl harness are disposed between an installment panel of a vehicle and a dash panel at the vehicle-body side. A power-source line, a signal line, and a ground line are present in each of the installment panel harness and the cowl harness. The junction box to be connected to the wire harness is assembled by connecting it to the installment panel harness or the cowl harness through a connector.
The cowl harness is disposed along a dash panel in an assembly line of a vehicle and fixed with a clamp. The installment panel harness is disposed along the installment panel and fixed with a clamp. In this state, the installment panel is installed on the dash panel. A front harness, a floor harness, a roof harness, and a door harness connector is fitted on a connector fit-on portion of a junction box connected to the installment panel harness or the cowl harness. Further a connector of the installment panel harness or the cowl harness at the side not connected to the junction box is fitted on the connector fit-on portion of the junction box. After required connectors are all fitted on the junction box, the junction box is fixed to the dash panel.
As described above, the power-supply line, the signal line, and the ground line are present in each of the installment panel harness and the cowl harness that are disposed on the installment panel and the dash panel. Further the wire harnesses and the junction box connected to the wire harnesses are also large. Thus, a large junction box-installing space is required. Also, it is difficult to install the junction box on the dash panel.
In connecting a large number of connectors to the junction box, it is necessary for an operator to extend her/his hand from below to a dark space sandwiched between the dash panel and the installment panel. The operator is crouching and stooping during installation. Thus, this operation is a physical burden on the operator. Further because it is necessary to connect the floor harness, the front harness, the roof harness, the door harness, and the installment panel harness or the cowl harness to the junction box, it is necessary to connect a large number of connectors on the junction box. Thus it takes a substantial amount of time to perform the connector connection operation.
To overcome the above-described problem, the present applicant proposed a junction box 1 as disclosed in Japanese Patent Application Laid-Open No. 9-154216 and as shown in FIG. 13. The junction box 1 is divided into a first junction box 2, with a common power-supply circuit, a ground circuit, and a high-current power supply circuit branch-connected to the common power-supply circuit and the ground circuit. The second junction box 3 has the low-current circuit which includes the signal circuit. The first junction box 2 and the second junction box 3 have the batch fit-on connector portions 2a and 3a, respectively. The relays and the fuses are mounted on the first junction box 2. The first junction box 2 is mounted on the installment panel P1 to connect it to the installment panel harness W/H1. The second junction box 3 is mounted on the dash panel P2. Further the junction box 1 has a plurality of harness/connector portions 3b that connect with the front harness, the floor harness, the roof harness, and the door harness.
The large junction box 1, which is later fixed to the dash panel, is divided into the high-current circuit and the low-current circuit to form the first junction box that is mounted on the installment panel in advance and the second junction box that is mounted on the dash panel in advance. Thus the internal circuit of each junction box has a simple compact construction. Further the first junction box and the second junction box are mounted on the installment panel and the dash panel, respectively, before the installment panel is mounted on the dash panel. Since the electrical connection is made when the installment panel is mounted on the dash panel, the junction box 1 has a function similar to that of a conventional junction box.
Through connectors, other wire harnesses are connected to the second junction box which is to be mounted on the dash panel. Thus, upon engagement of the batch fit-on connector portions, which are to be fitted on the first and second junction boxes, the installment panel harness can be connected to other wire harnesses. As described above, because of the connection between the first and second junction boxes, a batch connection between the installment panel harness and other wire harnesses can be achieved. Therefore the junction box proposed by the present invention enables the connector fit-on operation to be accomplished in a smaller number of processes than the conventional connector fit-on operation.
However, due to the disposition of the junction box between the dash panel and the installment panel it makes it difficult to perform maintenance work. In particular, where a large number of fuses and relays are used, the fuses and relays are mounted on both surfaces of each of the upper case and the lower case. Thus, it is difficult to perform a replacement operation of the fuses and the relays.
The internal circuit of the junction box is composed of bus bars. Thus, it is necessary to produce bus bars which depend on a circuit alteration, which increases the manufacturing cost. Further when a high-density circuit is required, the number of the bus bars increases and in turn, the junction box becomes large. Because the space between the dash panel and the installment panel is small, a large space is required to install the junction box. Furthermore because the junction box is connected to a wire harness of an external circuit through connectors, the number of component parts increases and numerous assembling stages are required in an assembling work, and so forth.
The present invention has been made in view of the above-described shortcomings of the art. Accordingly, it is a first object of the present invention to provide a junction box, disposed between a dash panel and a installment panel. Replacement of fuses and relays can be easily accomplished in a reasonable maintenance time. It is a second object of the present invention to provide a junction box capable of coping with a circuit alteration and having a small number of component parts and assembling stages.
Accordingly, the present invention includes a junction box disposed between a dash panel of a vehicle body and an installment panel. The junction box has a plurality of boxes removably connected to each other by overlapping the boxes on each other. A fuse and/or a relay accommodation portion is provided on one surface of each of the boxes.
In this construction, in an overlapped state, same-side surfaces of the fuse and/or relay accommodation portions of the boxes are exposed to the outside. Internal circuits of the overlapped boxes are connected to each other through a connector, a relay terminal or bolted terminal.
A plurality of boxes means the upper case and the lower case each accommodate an internal circuit. Unlike conventional junction boxes which have one box, the junction box of the present invention is divided into a plurality of boxes. Thus, circuits connected to electric component parts mounted on the installment panel are collectively accommodated in one box. Other circuits are collectively accommodated in another box. Therefore when circuit construction of the installment panel is altered, only the box for the circuit of the installment panel is altered. Thus the junction box is capable of easily coping with a circuit alteration.
By providing a plurality of boxes, it is possible to form the fuse and/or relay accommodation portion, with the same-side surfaces of the fuse and/or relay accommodation portions of the boxes exposed to the outside in an overlapped state. Thus, an operator can replace the fuses and the relays in only one direction at maintenance time.
Further the fuse accommodation portion and the relay accommodation portion are formed on one surface of each of the overlapped boxes. Therefore the horizontal sectional area of the junction box is not large. Further since a plurality of boxes are combined with each other, it is easy to conform the entire outer configuration of the junction box to the configuration of an installing space by varying the configuration of each box.
More specifically, the boxes are overlapped stepwise in two layers. The fuse and/or relay accommodation portion of each layer is disposed vertically. The fuse and/or relay accommodation portion confronts an opening/closing portion formed on a vertical frame portion of the installment panel.
In this construction, when an operator opens the opening/closing portion of the installment panel, the fuse-disposed surface and the relay-disposed surface of each of the upper and lower boxes confronts the opening/closing portion. Therefore the operator can easily accomplish maintenance which includes replacement of the fuses and relays.
In overlapping the upper box and the lower box on each other, fuses and/or relays to be mounted on the upper and lower boxes are separately disposed. Thus, a fuse and/or a relay mounted in the fuse and/or relay accommodation portion of the upper box are installed on a circuit connected to an electric component part mounted on the installment panel. A fuse and/or a relay mounted in the fuse and/or relay accommodation portion of the lower box are installed on a circuit connected to an electric component part other than the electric component part mounted on the installment panel.
As described above, depending upon the destination of a circuit to which fuses and relays are connected, fuses and relays are separately disposed on the upper and lower boxes. In this case, it is easy to find the box on which the fuse and/or relay which requires replacement is mounted. Also, it is easy to find the circuit to which the box requires inspection and repair is connected. Thus, high workability can be obtained in a reasonable maintenance time.
A bus bar and an electric wire are used as an internal circuit of the lower box. The internal circuit is connected to a power-supply line. A fuse and a relay of the lower box are connected to the bus bar and a wire harness inserted into the lower box without using a connector. A bus bar and a flat harness are used as an internal circuit of the upper box accommodating a printed wiring board. The bus bar and the flat harness are connected to a fuse, a relay, and the printed wiring board of the upper box. The flat harness is taken out to the outside from the upper box without using a connector to use the flat harness as an external wire harness.
Both upper and lower boxes are connected to an external wire harness without using a connector. Thus it is possible to reduce the number of component parts and improve workability in assembling the junction box. Further, numerous bus bars are not used for the internal circuit of the junction box. Electric wires and flat harnesses are utilized as the internal circuit of the junction box. Therefore the junction box is easily capable of coping with a circuit alteration.
The lower box is installed on the dash panel. The upper box is installed on the installment panel. In mounting the installment panel on the dash panel, the upper and lower boxes are connected to each other. The box may be loosely mounted on the dash panel or the installment panel. In this case, positions of the upper and lower boxes are adjusted and then the upper and lower boxes are connected to each other. Also, it is also possible to connect the upper and lower boxes to each other and then mount them on one of the panels.
In order to simultaneously mount the installment panel on a dash board and connect the upper and lower boxes to each other, connectors on the upper box and the lower box are movably fitted on each other through an elastic supporting member by utilizing a clearance between connector housings of the upper box and the lower box. When the upper box and the lower box are connected to each other, positions of the connectors are automatically adjusted.
In the case where the positions of the upper and lower boxes are adjusted and then the upper and lower boxes are connected to each other; and in the case where the operation of connecting the upper and lower boxes to each other is performed separately from the operation of fixing the installment panel and the dash panel to each other; connectors of the upper box and the lower box fit on each other when the upper box and the lower box are connected to each other with a lever or when the upper box and the lower box are connected to each other with a bolt.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.